Messages in this thread | | | Date | Fri, 27 Mar 2015 13:14:48 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH] mm/x86: AMD Bulldozer ASLR fix |
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* Hector Marco-Gisbert <hecmargi@upv.es> wrote:
> A bug in Linux ASLR implementation which affects some AMD processors > has been found. The issue affects to all Linux process even if they > are not using shared libraries (statically compiled).
It's not a bug, it's a feature: to work around a Bulldozer cache aliasing performance problem we have to keep bits 12,13,14 equal for all mappings in the system.
Your patch improves upon that fix: by per-boot randomizing the constant portion of the randomized range.
Btw., does anyone know how relevant the performance fix is these days? A simpler improvement would be to remove the workaround altogether and recover proper randomization of bits 12,13,14.
Thanks,
Ingo
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